Vibration isolating proof device

ABSTRACT

An oscillation limiting mechanism  4  is integrally provided to an engine mount  3  (a vibration proof mount device) of a power plant P mounted on an automobile in a traverse mount fashion. Not only is a stopper metal member  40  in the shape of an inverted U letter disposed so as to cross over a mount body portion  30,  but a stopper rubber  42  is formed so that it protrudes from the rear end of a casing of the mount body portion  30  toward the rear side of the vehicle body. Not only is a hollow portion  43  formed in the interior of the stopper rubber  42,  but a metal core body  44  is also embedded in the stopper rubber  42  so as to be revolvable around an axis in the vehicle body traverse direction as if it were a link. With such a construction adopted, the stopper rubber  42  is shear-deformed in the vertical direction with comparative ease even in a state where it is brought into contact with the rear side leg portion  40   c  of a stopper metal member  40  and thereby receives a compressive force in the vehicle body longitudinal direction, and a dynamic spring constant of the mount  3  in the vertical direction does not rise so much even if the stopper acts in rapid acceleration or the like; therefore, enabling increase in surrounding sound in acceleration to be suppressed with a simple structure less of cost up while oscillation of the power plant P is limited in a similar way to that of a torque rod.

BACKGROUND OF THE INVENTION

The present invention relates to a vibration isolating proof device formounting a power plant on an automobile, and particularly, belongs tothe technical field of a structure thereof in a case where a mechanismfor limiting oscillation in a rolling direction of the power plant isinstalled integrally in a single body.

In a front engine-front drive (FF) type vehicle, for example, generallya power plant has been conventionally mounted on the vehicle body withthe length direction (a direction along which a crankshaft extends)thereof aligned in the width direction of the vehicle body so that bothend portions thereof are elastically supported by the body side frameslocated on both sides, left and right, of the engine room (a so-calledtraverse mount type).

As such a traverse mount type, main stream thereof is an inertia mainaxis mount scheme (or a torque roll axis scheme) in which main mounts onboth ends, left and right, of the power plant are disposed in theproximity of a roll inertial main axis (hereinafter referred to simplyas a roll axis) thereof, which is disclosed, for example, in Patentliterature 1 (FP No. 2736008 A). This is because a dynamic springperformance around the roll axis is made comparatively softer with asecured support stiffness of two mounts on the left and right sides,respectively, supporting almost all the static load of the power plant,thereby enabling idle vibrations to be effectively reduced.

With the dynamic spring performance around the roll axis softer to suchan extent, for example, when a driving output (torque) of the enginegreatly alters as in rapid acceleration or rapid deceleration in thecase of the torque roll axis mount, the power plant in the entiretygreatly rolls around the roll axis by the reaction force (torque);therefore, plural mounts for limiting the rolling are usually providedbefore and after the power plant in addition to the main mounts on theleft and right sides.

In this connection, another mount scheme is disclosed, for example, inPatent literature 2 (DP No. 4209613 A) in which supporting points for apower plant of main mounts on the left and right sides not only are setmore higher than a roll axis to thereby oscillatably support the powerplant in the entirety but also dispose a torque rod for limiting theoscillation at the lower end portion thereof so as to connect the powerplant to the vehicle body side (this scheme is hereinafter referred toas a pendulum mount scheme).

Since in the pendulum mount scheme, main mounts on the left and rightsides are farther away from a roll axis than in the general torque axismount scheme, a force in the vehicle body longitudinal direction actsdirectly on the main mounts in company with rolling of the power plant;in other words, the rolling is limited by the mounts themselves. Inconsideration of this, according to the mount scheme described in Patentliterature 2, torque rods are provided to the main mounts on the leftand right mounts, respectively, in addition to an independent torque rodattached at the lower end of the power plant, thereby causing a force inthe vehicle body longitudinal direction to be received.

In a case where torque rods are provided to the main mounts in such away as well, however, the number of parts constituting the mountsincreases correspondingly to thereby raise the number of assemblyman-days; therefore, leading to a problem to cause a lot of cost up.This is because both ends in the front and rear sides of each of thetorque rods are supported so as to be revolvable around respectivehorizontal axes so that a vertical motion of the corresponding mount isnot hindered by attachment of the torque rod and the torque rod isconnected to the corresponding mount with a rubber bush so thatvibration is not transmitted to the mount.

In connection with this aspect, there has been known various kinds ofstopper mechanisms capable limiting displacement in a mount with asimpler structure. In a mount scheme described, for example, in Patentliteratures 3 and 4 (JP No. 2003-184939 A and JP No. 2002-257182 A),stopper rubber portions are provided so as to protrude on both sidesbefore and after a member connected to the power plant side and thestopper rubber portions are brought into contact with members of thevehicle body side which the stopper rubber portions face in the vehiclebody longitudinal direction, thereby preventing displacement beyond themembers of the vehicle body side.

Since, if the stopper rubber portions are, in such a way, brought intocontact with the vehicle body, an adverse possibility arises thatvibrations of the power plant are transmitted to the vehicle body sidethrough the stopper rubber portion, stopper mechanisms described inPatent literatures 5 and 6 (JP No. 61-92329 A and JP No. 60-02541 B)each are equipped with the stopper rubber portion having protrudedstripes at the distal end thereof or the stopper rubber portion having ahollow in the interior thereof, thereby reducing a stiffness thereofpartly. With partial reduction in the stiffness, no increase in springconstant of the mount occurs suddenly at the same time as the action ofthe stopper (S1), for example, as shown with a solid line (I) of FIG. 7Aand increase in spring constant at an initial stage of the action of aspring occurs in a relatively mild manner, thereby enabling vibrationsto be absorbed, as shown with a broken line (II) in the same figure.

The conventional stopper mechanisms (disclosed in Patent literatures 3to 6 and the like) each, however, have no function that an increase indynamic spring constant in the vertical direction can be restricted tothe lowest level without hindering upward and downward motions of amount by receiving and absorbing a force in the vehicle bodylongitudinal direction acting on the mount as a torque rod acts, so themechanisms each cannot be a substitute for the torque rod.

That is, in the stopper mechanisms of Patent literatures 3 and 4, asdescribed above, since elastic deformation of compressed rubber isgreatly limited not only in the vehicle body longitudinal direction butalso in the vertical direction in a state where the stopper rubberportion is in contact with a member of the vehicle body to receive apushing force in the vehicle body longitudinal direction, the member ofthe vehicle body is restricted in motion thereof by the rubber stopperportion relative to the member of the power plant. For this reason,dynamic spring constants of the mount in the entirety in thelongitudinal direction and vertical direction of the vehicle bodyincrease suddenly at the same time as the action of the stopper, therebydegrading vibration proof performance (see the solid lines shown in thegraphs of FIGS. 7A and 7B).

In acceleration of an automobile, for example, a power plant in theentirety, in some case, has great vibrations in the vertical directionbecause of unbalance in reciprocating inertia force or the like of theengine, when the power plant is inclined by a driving reaction force tothereby cause a stopper to act and to degrade vibration proofperformance of mounts suddenly, which leads to an inconvenience thatvibrations in the vertical direction accompanying the accelerationoperation propagates into the vehicle compartment to generate a loudsurrounding sound confined therein.

Even if stiffness of the stopper rubber portion is partly reduced tocope with such an inconvenience to thereby cause rubber to beelastically deformed with comparative ease at the initial stage in theaction of a stopper, as shown in Patent literature 5 and 6 describedabove (see the broken line in the graph of FIG. 7A), such a featureworks only so as to slow down degradation of vibration proof performanceof a mount in company with action of the stopper, and does not work suchthat increase in dynamic spring constant in the vertical direction ofthe mount as a whole is suppressed to thereby enable vibrations in thevertical direction to be sufficiently absorbed while a load in thevehicle body longitudinal direction is received with certainty, as atorque rod works.

SUMMARY OF THE INVENTION

The present invention has been made in light of such problematic pointsand it is an object of the present invention to provide a vibrationisolating proof device for an engine (or a power plant) in a traversemount fashion in a so-called FF automobile or the like in which anoscillation limiting mechanism provided therein integrally provided in asingle piece is deliberately contrived in construction so as to achievea function similar to that of a torque rod while a simple structurethereof less of cost up is realized.

In means adopted by the present invention for the purpose to achieve theobject, a basic structure of a conventional known stopper mechanism isemployed and, for example, a core body of a receiving member for a forcein the vehicle body longitudinal direction such as a stopper rubber orthe like is caused to revolve as if it were a link to thereby cause thereceiving member for a force in the vehicle body longitudinal directionto be subjected to shear deformation in the vertical direction withcomparative ease even when the receiving member receives a compressiveforce in the vehicle body longitudinal direction, thereby enabling amember of a vehicle body and a member of a power plant to displacerelatively to each other in the vertical direction with comparativeease.

To be more concrete, a first invention of the present application isdirected to a vibration isolating proof device not only for elasticallysupporting one of left and right end portions of a power plant mountedon a vehicle with the length direction of the power plant aligned in thetraverse direction of the body of the vehicle, but also having anoscillation limiting mechanism for limiting oscillation of the powerplant in a roll direction thereof. The oscillation limiting mechanismhas a receiving member for a force in the vehicle body longitudinaldirection receiving at least a compressive force in the vehicle bodylongitudinal direction between a member of the vehicle body and a memberof the power plant facing each other in the vehicle body longitudinaldirection, and the receiving member for a force in the vehicle bodylongitudinal direction (hereinafter referred to simply as the receivingmember) is constructed of: a rubber portion and a core body made of amaterial higher in stiffness than the rubber portion and providedintegrally with the rubber portion in a single piece at least so as tobe revolvable around an axis in the vehicle body traverse direction by apredetermined angle or more.

With the mechanism adopted, the power plant revolves (rolling) aroundthe roll axis by the action of a driving reaction force, for example, inacceleration and deceleration of an automobile to thereby cause thereceiving members between the members of the power plant and the vehiclebody to receive a force in the vehicle body longitudinal direction whenthe member of the vehicle body and the member of the power plant aredisplaced relatively from each other in the vibration limiting mountdevice, thereby enabling oscillation of the power plant to be limited.

In this situation, a rubber portion of the receiving member iscompressed in the vehicle body longitudinal direction and thereby causedto be in a state of difficulty in elastic deformation, while the corebody provided integrally in the receiving member as a single piecerevolves as if it were a link (which is also hereinafter referred to asa link action), thereby shear-deforming the receiving member as a wholein the vertical direction with comparative ease. With such construction,since the members of the vehicle body and the power plant can bedisplaced relatively from each other, absorption of vibrations in thevertical direction is performed sufficiently.

That is, according to an oscillation limiting mechanism of the inventionof the present application, even with a simple structure similar to thatof a conventional general stopper mechanism, a function similar to thatof a torque rod is achieved by a link action of a core body providedintegrally with a rubber portion, which is different in function fromthe conventional general mechanism, thereby enabling absorptionperformance of vibrations in the vertical direction in a vibration proofmount to be sufficiently maintained while oscillation of the power plantis limited effectively.

Note that to provide the core body in the receiving member so as to berevolvable by a predetermined angle or more is to construct a structurein which the core body is intentionally revolved, which is differentfrom a structure in which a core metal or the like is embedded in aconventional known stopper rubber for reinforcement. Therefore, in theinvention related to claim 1, the core body in the receiving member canusually revolve relatively to at least one of a member of a vehicle bodyand a member of a power plant by a predetermined angle (for exampleabout 1 degree) or more, for example when the receiving member receivesa force in the vertical direction without the action of a force in thevehicle body longitudinal direction.

In the first invention, a hollow portion is preferably formed in therubber portion of the receiving member at least so that the core bodycan be revolved around an axis in the vehicle body traverse direction (asecond invention).

For example, it is recommended that the hollow portion of the receivingmember is formed so as to communicate with outside the rubber portionand at least one of inner walls in the front and rear portions of therubber portion enclosing the hollow portion is caused to swellrelatively into the hollow portion on one of the upper and lower sidesthereof and to thereby at least embed the core body in the swell portion(a third invention). It is preferable that the hollow portion is formedso as to pass through the rubber portion in the vertical direction andthe swell portion is formed at a site relatively in the lower side inthe hollow portion (a fourth invention).

With such a construction, when the receiving member receives acompressive force between the members of the vehicle body and of thepower plant and the hollow portion thereof is collapsed by elasticdeformation of rubber, part of the hollow portion remains uncollapsed onone of the upper and lower sides of the swell portion where the corebody is embedded; therefore, the core body can be revolved in thevertical direction with comparative ease even in a state where therubber is compressed, thereby ensuring the action and effect of thefirst invention to be more certain.

Alternatively, in the first invention, the core body in the receivingmember may be in the shape of a rectangle the length of which in thevehicle body longitudinal direction is more than the length in thevehicle vertical direction as viewed in the traverse direction of thevehicle body (a fifth invention).

With a shape of the core body having a dimension comparatively longer inthe vehicle body longitudinal direction, the core body can perform alink action without forming the hollow portion in the rubber portion,thereby enabling almost the same action and effect as those of thesecond invention.

Moreover, in the first invention, the core body in the receiving memberis preferably provided so as to be revolved by receiving a compressiveforce acting between a member of the vehicle body and a member of thepower plant (a sixth invention).

With the construction, when the receiving member receives a compressiveforce between the member of the vehicle body and the member of the powerplant, the receiving member as a whole is urged to receive sheardeformation in the vertical direction by revolution of the core body;therefore, displacement in the vertical direction of the members of thevehicle body and the power plant is facilitated with more of ease,leading to more of certainty of the action and effect of the firstinvention.

In the receiving member, for example, it is preferable that the rubberportion includes: a connecting portion connecting the core body to oneof the member of the vehicle body and the member of the power plant; anda protruded end portion directed to the other member thereof from thecore body, wherein the connecting portion and protruded end portion arevertically shifted in an offset arrangement (a seventh invention).

With such a construction, by bringing the protruded end portion (therubber portion) of the receiving member provided on one of the member ofthe vehicle body and the member of the power plant into contact with theother member thereof to push the protruded end portion in the vehiclebody longitudinal direction, the pushing force from the other memberthereof and the reaction force from the one member thereof constitute acouple of forces to thereby generate a revolving force (a moment) on thecore body.

Note that the term, offset, means off centering in general and forexample, means that the connecting portion and the protruded end portionof the rubber portion are vertically shifted in center from each other,that horizontal lines having centers of gravity of both thereon,respectively, are vertically shifted from each other, that applicationpoints of forces acting thereon in the vehicle body longitudinaldirection is vertically shifted from each other or the like.

A construction is allowed in which the core body in the receiving memberassumes a crank-like shape as viewed in the vehicle body traversedirection and the front end portion and the rear end portion arevertically shifted in an offset arrangement (an eighth invention) or inwhich the core body is inclined so that the front end portion and rearend portion are vertically offset in position (a ninth invention).

With such constructions, when the receiving member between the member ofthe vehicle body and the member of the power plant is pushed from beforeand after, a couple of forces acts thereon in a similar manner to thatin the seventh invention to revolve the core body. In order to obtainsuch an action with more of certainty, it is allowed to form a hollowportion at a proper site in the rubber portion.

An example is presented here as a preferable concrete structure of avibration isolating proof device related to one of the second to ninthinventions, in which a member of the vehicle body in the shape of aninverted U letter is disposed so as to cross over the body of the mounton which a static load of the power plant is imposed to fix the lowerends of leg portions of a pair located before and after the member ofthe vehicle body to a side frame of the vehicle body at positions beforeand after, respectively, the body of the mount. The receiving member isdisposed at at least one of the front and rear sites of an outer wallportion of the body of the mount, which is the member of the powerplant, so as to protrude toward a leg portion of the member of the bodyof the vehicle which the receiving member faces in the vehicle bodylongitudinal direction (a tenth invention).

With the construction, not only is the member of the vehicle body in theshape of an inverted U letter provided so as to cross over the body ofthe mount connected to the power plant, but the receiving member is alsodisposed on the outer wall portion of the body of the mount, and in acase where the receiving member is provided at one of the front and rearsides or both sides of the body of the mount as well, the receivingmember or members can be integrally molded in a single piece with thebody of the mount in a similar manner to that in a conventional knownstopper rubber, resulting in reduction in cost.

In another concrete construction of the first invention, it ispreferable that members of the vehicle body are provided before andafter members of the power plant so as to face each other and a rubberportion of the receiving member is provided on one of the member of thepower plant and the corresponding member of the vehicle body. The corebody of the receiving member not only is inclined by a predeterminedangle relative to a horizontal plane in the vehicle body longitudinaldirection, but is also disposed so as to surround the member of thepower plant across more than a half of the circumference from one of theleft and right sides so as to receive a compressive force in the vehiclebody longitudinal direction between the member of the power plant andthe corresponding one of the members in the front and rear sides of thevehicle body (an eleventh invention).

With such a construction, since the core body in the receiving member isinclined relative to a horizontal plane even when the receiving memberfor a force in the vehicle body longitudinal direction receives acompressive force acting between the member of the vehicle body and themember of the power plant in acceleration and deceleration of anautomobile, the core body revolves as if it were a link without beingrestricted strongly by the compressive force, thereby facilitate thereceiving member as a whole to be subjected to shear deformationvertically with comparative ease. With such shear deformation withcomparative ease, the action and effect of the first invention can beobtained with more of certainty.

In addition, in the acceleration and deceleration, a compressive forceoccurring between the member of the power plant and the correspondingone of the members of the vehicle body can be received by one receivingmember; therefore enabling a structure having a function similar to thatof a torque rod forward or backward in the vehicle body longitudinaldirection to be realized at a low cost.

In the eleventh invention, it is preferable that the rubber portion ofthe receiving member is provided to the member of the power plant and aflat plane portion in almost parallel to a surface of the member of thevehicle body which the flat plane faces is formed at at least one endportion of the front and rear sites of the core body (a twelfthinvention).

With such a construction, when one end portion of the front and rearsites of the receiving member for a force in the vehicle bodylongitudinal direction is brought into contact with the member of thevehicle member by displacement of the member of the power plant in thevehicle body longitudinal direction, the core body of the receivingmember receives a pushing force uniformly over the entire surface of theflat plane portion, preventing damage or the like in the rubber portionsandwiched therebetween.

It is more preferably that the rubber portion of the receiving member isprovided to the member of the power plant and a surface with a circulararc in section swelled in the middle of the vertical width is formed atat least one end portion of the front and rear sites of the core body (athirteenth invention).

With such a construction, the link action of the core body can be moreeasily realized as compared with the case where the one end surface ofthe core body is of a flat plane.

In order to obtain a core body in the receiving member in apredetermined inclined state, the rubber portion is necessary to becured in a state where the core body is held obliquely relative to ahorizontal direction, wherein the receiving member is supported by pinmembers so that the core body obtains an inclined state of being held ata predetermined angle relative to a horizontal plane in the vehicle bodylongitudinal direction and then integrated with the rubber portion in asingle piece.

Accordingly, in a case where the core body is embedded in the rubberportion at least at both of the front and rear sites of the member ofthe plant power, and holes (in which the pin members are inserted incure molding of the rubber portion) are formed that extend in thevertical direction down or up to a surface of the core body in therubber portion from the upper or lower surface of the rubber portion atsites thereof corresponding to sites on the front and rear portions ofthe core body so that height positions of the bottoms of the holes onthe front and rear portions of the core body are different from eachother (a fourteenth invention).

As described above, according to a vibration isolating proof devicerelated to the invention of the present application, in a case where anoscillation limiting device is provided instead of a torque rod asfunctional replacement in the vibration proof mount of a power plantmounted in a traverse mount fashion in an engine room of an automobile,a basic structure of a conventional known stopper mechanism is employed:for example with a core body in a receiving member for a force in thevehicle body longitudinal direction such as a stopper rubber so as torevolve around an axis in the vehicle traverse direction as if it were alink provided, the receiving member for a force in the vehicle bodylongitudinal direction is shear-deformed in the vertically, directionwith comparative ease when the receiving member receives a compressiveforce in the vehicle body longitudinal direction; therefore, not onlycan a load in the vehicle body longitudinal direction be received andabsorbed with certainty as a torque rod does, though with a simplestructure less in cost up, but also no dynamic spring constant suddenlyincrease in the vertical direction and the surrounding sound due toacceleration of automobile can be sufficiently suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a schematic construction of anengine mount system.

FIG. 2 is a descriptive view as a model of a power plant showing a waythat a driving reaction force (torque) acts as viewed from the left sideof the body of a vehicle.

FIG. 3 is an enlarged upper surface view showing a structure of a mounton the engine side of an embodiment 1.

FIG. 4 is a left side view of FIG. 3.

FIG. 5 is a partially sectional view showing an internal structure ofthe body of a mount.

FIGS. 6A and 6B are enlarged sectional views as a model showing astructure and workings of a oscillation limiting mechanism.

FIG. 7A is a graph for a load vs. displacement showing a change instatic spring characteristic in the vehicle body longitudinal directionof a mount in company with acceleration and deceleration of anautomobile and FIG. 7B is a graph showing changes in dynamic springcharacteristic in the vertical direction before and after action of astopper.

FIG. 8 is a view related to an example modification having a feature ina shape of a core body corresponding to FIG. 3.

FIG. 9 is a view related to an example modification without providing ahollow portion corresponding to FIGS. 6A and 6B.

FIG. 10 is a view related to an embodiment 2 corresponding to FIG. 3.

FIG. 11 is a view related to the embodiment 2 corresponding to FIG. 4.

FIG. 12 is a view related to the embodiment 2 corresponding to FIG. 5.

FIGS. 13A and 13B are views related to the embodiment 2 correspondingFIGS. 6A and 6B.

FIGS. 14A, 14B, 14C and 14D are views related to an example modificationof the embodiment 2 corresponding to FIG. 13A.

FIG. 15 is a view related to an embodiment 3 corresponding to FIG. 1.

FIG. 16 is a view related to the embodiment 3 corresponding to FIG. 5.

FIG. 17 is a view related to the embodiment 3 corresponding to FIG. 3.

FIG. 18A is a perspective view showing a core body in an isolated stateand FIG. 18B is an example modification having an outer circumferentialsurface in the shape of a circular arc in section.

FIGS. 19A and 19B are views related to the embodiment 3 corresponding toFIGS. 6A and 6B.

DETAILED DESCRIPTION OF THE INVENTION

Detailed description will be given of embodiments of the presentinvention below with reference to the accompanying drawings. Note thatit should be understood that description of the following preferableembodiments are presented in essence only by way of illustration and isnot intended to restrict the present invention, products to which thepresent invention is applied or applications of the present invention.

Embodiment 1

FIGS. 1 and 2 show a schematic construction of an engine mount systemusing a vibration isolating proof device related to the embodiment 1 ofthe present invention. In both figures, a mark P is a power plantconstructed by coupling in series an engine 1 and a transmission 2 toeach other. The power plant P is mounted in an engine room of anautomobile not shown in a traverse mount fashion so that the lengthdirection thereof (a direction in which a crankshaft of the engine 1extends) takes a vehicle width direction (a vehicle body traversedirection) and elastically supported by vehicle body side frames 6 and 7at two sites thereof through mounts 3 and 5 disposed at both endportions in the length direction, that is at end portions on the side ofthe engine 1 thereof and the side of the transmission 2 thereof. Thelower end portion of the power plant P is connected to a vehicle bodyside member 9 (a subframe or the like) in the rear side of the vehiclebody by a torque rod 8 independent of the mounts 3 and 5.

FIG. 1 shows an outer appearance only of the body of the power plant asviewed obliquely from the upper right position at the rear side of thevehicle body omitting all of an intake-exhaust system, auxiliaryequipment thereof and the others of the engine 1 and the body of theengine 1 roughly includes: a cylinder block 10 and a cylinder head 11arranged thereon and in addition, is provided with a belt cover 12 at anend portion in the length direction opposite the transmission 2 (theright end portion of the vehicle body shown in FIG. 1 at the frontthereof) and further not only a head cover 13 on the top of the cylinderhead 11 but also an oil pan (not shown) in the lower portion of thecylinder block 10. The lower end side of an engine side mount bracket 15is fastened to the right side wall of the cylinder head 11 passingthrough the belt cover 12 and a flange plate 31 b extending from themount 3 side is fastened, in a state of being superimposed from above,onto the upper end portion of the mount bracket 15 extending upward fromthe lower end thereof. The engine side mount 3 is vibration isolatingproof device of the present invention and description will be given ofdetails of the construction later.

The transmission 2 in this embodiment is an automatic transmission(which, instead, may be a manual transmission, CVT or the like)constructed from a torque converter, a transmission gear train and inaddition thereto a differential gear integrated in a single piece andnot only is a bell housing 20 a of the transmission case 20 is connectedto the cylinder block 10 at a crankshaft side end portion of the engine1, but driveshafts 22 and 22 for driving the front wheels of anautomobile also extend from a swell portion 20 b formed on the rear sideof the bell housing 20 a toward both sides in the vehicle traversedirection. The transmission side mount 5 is disposed in a manner suchthat the transmission case 20, at a position in the vicinity of thedistal end toward which the transmission case 20 is tapered, is hungdown from the side frame 7 in the left side of the vehicle body by amount bracket 23.

In the power plant P constructed by coupling in series the engine 1 andthe transmission 2, since the engine 1 is higher than the transmission2, a roll axis R (a roll inertia main axis) extending the lengthdirection is inclined downward in a direction from an end portion of theengine 1 side to the transmission 2 side as shown with an alternate longand short line in the figure. In this embodiment, the two mounts 3 and 5sharing a weight of the power plant P therebetween is spaced upward fromthe roll axis R, whereby the power plant P can oscillate like a pendulumaround a line segment L (an oscillation support axis: see FIG. 2)connecting between load support points of the two mounts 3 and 5.

When a large driving reaction force (a torque) acts, for example, as inrapid acceleration or rapid deceleration of an automobile, the powerplant P tends to oscillate forward and rearward like a pendulum as awhole with the oscillation axis L thereabove as a center while revolvingalmost around the roll axis R, as shown as a model with an open arrowmark in FIG. 2, whereas such a rolling and an oscillation thereof as awhole are not only restricted mainly by the torque rod 8 disposed in thelower end of the power plant P but also restricted by the oscillationlimiting mechanisms 4 (see FIGS. 3 to 5) disposed in the left and rightmount 3 and 5.

That is, in this embodiment, as described above, the oscillationlimiting mechanisms having a function similar to that of a torque rodare provided in the left and right mounts 3 and 5 in addition to theindependent torque rod 8 disposed in the lower end portion of the powerplant P, and even if the power plant P is caused to roll by a drivingreaction force or the like in the acceleration to impose a large load inthe vehicle body longitudinal direction on the mounts 3 and 5, the loadis received and absorbed by the oscillation limiting mechanisms tothereby restrict oscillation of the power plant P with more ofcertainty.

—Structure of Engine Side Mount—

Then, description will be given of details of the structure of theengine side mount 3 of the two mounts 3 and 5 on the engine side andtransmission side with reference to FIGS. 3 to 5. FIG. 3, herein, is anupper surface view of the engine side mount 3 and FIG. 4 is a left sideview thereof. FIG. 5 is a partially sectional view showing an internalstructure of the body 30 of a mount part of which is cut away. Note thatwhile detailed description is omitted of the transmission side mount 5,the basic structure is of a conventional known one.

In this embodiment, as shown in FIG. 5, the engine side mount 3 is aso-called liquid sealed type and the mount body 30 supporting a staticload of the power plant P is constructed from a metal casing 31 (amember of the power plant side) connected to the power plant side and aconnecting metal member 32 of the vehicle body side, both of which areconnected by a rubber elastomer 33. The casing 31 is made of, forexample, an aluminum alloy and is constructed from a casing body 31 a(an outer wall portion) in the shape of a thick wall cylinder disposedso as to extend vertically and a flange plate 31 b extending from theouter circumference in the upper side of the casing body 31 in adirection intersecting with an axial line Z at an almost right angle,both of which are fabricated by casting or the like in a single piece.

The connecting metal member 32 is in the shape of a near circular conetapered at the top thereof and disposed concentrically with the casingbody 31 a so that the top end portion thereof is located almost at thecenter of the lower end opening of the casing body 31 a, and the rubberelastomer 33 is interposed between the tapered side surface portion andthe inner circumferential surface of the casing body 31 a facing theouter circumferential surface of the connecting metal member 32. On theother hand, an upward swell portion 34 a of a mount bracket 34 on thevehicle body side fixed on the upper surface of the vehicle side frame 6is joined to the lower end surface of the connecting metal member 32 andboth are fastened to each other with a bolt 35.

The rubber elastomer 33 is formed so as to have a lower innercircumferential surface in the shaped of an inverted cone recess and acircumferential surface of the recess is adhered to the tapered sidesurface portion of the connecting metal member 32. The rubber elastomer33 is shaped such that it expands outward radially and obliquely upwardfrom all of the periphery of the connecting metal member 32 to formalmost the shape of a frustum of a circular cone and the outercircumferential surface thereof is adhered to the inner circumferentialsurface of the casing body 31 a. The upper side portion of the rubberelastomer 33 fixedly adhered to the inner circumferential surface of thecasing body 31 a is in the shape of a cylinder having a comparativelythick wall and open upward and the top end portion thereof is locatedlower than the top end portion of the casing body 31 a by apredetermined length.

A partition plate 36 in the shape of a disk is superimposed, from above,on the top end portion of the rubber elastomer 33 and a rubber diaphragm37 almost in the shape of a hat is provided so as to cover the partitionplate 36 from above. With such a construction, the top end opening ofthe rubber elastomer 33 is liquid-tightly closed to form a cavitysection in the interior thereof. A reinforcing plate 38 almost in theshape of a cylinder is embedded in the outer circumferential side of thediaphragm 37 and the outer circumferential portion reinforced thereby ispress inserted from above in the top end side of the casing body 31 aand fixed in an internally fitting state.

A shock absorbing liquid such as ethylene glycol is sealed in the cavityportion defined as described above in the interior of the rubberelastomer 33 to form a liquid chamber F for absorbing and alleviatingvibrations of the power plant P caused by a force applied to the rubberelastomer 33. The interior of the liquid chamber F is partitioned intotwo spaces one on the other by the partition plate 36 and the lowerspace serves as a pressure-receiving chamber a volume of which expandsor shrinks in company with deformation of the rubber elastomer 33. Theupper space of the liquid chamber F serves as an equilibrium chamber avolume of which is expanded or shrunk by deformation of the diaphragm 37to absorb a change in volume of the pressure-receiving chamber.

That is, an annular orifice passage 39 surrounded with the casing body31 a, a flange portion and an inner cylindrical portion of the diaphragm37 is formed so as to extend in a circumferential direction in the upperpart of the outer circumferential portion of the partition plate 36 andone end of the orifice passage 39 face and is open in thepressure-receiving chamber in the lower side of the liquid chamber 38,while the other end of the orifice passage 39 faces and is open in theequilibrium chamber in the upper side of the liquid chamber F. The shockabsorbing liquid in the pressure-receiving chamber and the equilibriumchamber communicate with each other through the orifice passage 39 tothereby attenuate vibrations of low frequencies acting on thepressure-receiving chamber From the rubber elastomer 33.

—Oscillation Limiting Mechanism—

An oscillation limiting mechanism 4 that is a feature of the inventionof the present application is generally provided to the engine sidemount 3 as shown in FIGS. 3 to 5 in addition to the mount body portion30 with a structure as described above. Note that while detaileddescription is omitted, an oscillation limiting mechanism having asimilar function is installed in the transmission side mount 5 as well.

A stopper metal member 40 (a member of the vehicle side) in the shape ofan inverted U letter fabricated by press working of a steel sheet or thelike is attached to the vehicle body side frame 6 so as to cross overthe mount body portion 30 from the front side to the rear side thereof.The stopper metal member 40 has a beam portion 40 a extending in adirection from the front side to the rear side of the member almosthorizontally above the mount body portion 30 and a pair of leg portions40 b and 40 c extending downward from both end portions thereof asextensions of the beam 40 a. The lower end portions of the pair of legportions 40 b and 40 c are further bent to form flange portions 40 d and40 e, and the flange portions 40 d and 40 e are fastened with bolts notshown on the side frame 6 in the state of being overlapped on flangeportions 34 b and 34 b of the vehicle body side mount bracket 34 at thefront and rear sides of the mount body portion 30.

Note that in the figures, there is shown the mount body portion 30 inthe state without a load imposed thereon and in this state, the uppersurface of the casing 31 of the mount body portion 30 and the beamportion 40 a of the stopper metal member 40 are close to each other,while in a state of 1 G where the engine side mount 3 is attached to thevehicle body and a static load of the power plant P acts on the mountbody portion 30, since the rubber elastomer 33 is deformed, though notshown, to displace the casing 31 downward, a predetermined clearance isformed between the upper surface of the casing 31 and the beam portion40 a of the stopper metal member 40.

On the other hand, stopper rubbers 41 and 42 are provided on the upperend portions at the front and rear ends of the outer circumferentialsurface of the casing body 31 a so as to correspond to the leg portions40 b and 40 c of the stopper metal member 40 in the front and rear sidethereof. The stopper rubbers 41 and 42 on the front and rear ends of thecasing body 31 a are brought into contact with the respectivecorresponding legs 40 b and 40 c in the front and rear sides of thestopper metal member 40 to thereby limit movement of the casing body 31a in the vehicle body longitudinal direction, wherein especially thestopper rubber 42 on the rear side in the vehicle body longitudinaldirection is provided in the interior thereof with a hollow portion 43formed in a characteristic way described below and a core body 44 isembedded therein, thereby exerting a function equal to that of a torquerod.

Upward swell portions 41 a and 42 a raised upwardly on the upper surfaceof the casing body 31 a are formed as parts of the stopper rubbers 41and 42 on the front and rear ends of the casing body 31 a and the upwardswell portions 41 a and 42 a are brought into contact with the beamportion 40 a of the stopper metal member 40 from below to thereby limitupward movement of the casing body 31 a. On the other band, an annularrubber layer 45 is formed on the outer circumferential surface of thelower end portion of the casing body 31 a so as to work in cooperationwith the rubber elastomer 33 and the both of the front and rear ends ofthe rubber layer 45 are swelled downward and the downward swell portions45 a and 45 b are brought into contact with the upward swell portion 34a of the vehicle body side mount bracket 34, thereby limiting downwardmovement of the casing body 31 a.

Detailed description will be given of a structure of the rear sidestopper rubber 42 with reference to FIGS. 6A and 6B. The rear sidestopper rubber 42, as shown in FIG. 6A, has a long narrow hollow portion43 vertically passing through the interior of a rubber blockcure-adhered onto the outer circumferential surface of the casing body31 a formed in a fabrication process of the mount body portion 30, andat the same time, the metal core body 44 in the shape of a rectangularplate is disposed so as to be adjacent to the hollow portion 43, and incooperation with each other, the rear side stopper rubber 42 can beshear-deformed with comparative ease while receiving a pushing force inthe vehicle body longitudinal direction.

To be detailed, the rear side stopper rubber 42 has the shape of arectangular block as a whole and has a rubber block portion 42 b locatedin the front side and a rubber wall portion 42 c located in the rearside with the hollow portion 43 (see FIG. 3) in the sectional shape of arectangle as viewed in the vertical direction interposed therebetween.The inner surface (the inner wall surface surrounding the rear side ofthe hollow portion 43) of the rubber wall portion 42 c thereof swellsinward in a relative sense at a site in the lower side thereof and thecore body 44 is embedded in the swell portion 42 d. That is, the hollowportion 43 has the sectional shape with a stepped structure wherelengths in the vehicle body longitudinal direction in the upper andlower sides are different from each other as viewed from in the vehiclebody traverse direction as shown in FIG. 6A (a stepped hollow portion).

With such a construction, as shown in FIG. 6B, when the rear end surfaceof the rear side stopper rubber 42 is brought into contact with the rearside leg 40 c of the stopper metal member 40 to receive a pushing forcein the vehicle body longitudinal direction, the swell portion 42 dhaving an area equal to or more than almost a half of the inner wallsurface in the rear side of the hollow portion 43 is brought intocontact with the rubber block portion 42 b in the front side to therebyreceive and absorb a force in the vehicle body longitudinal directionwith certainty. In this situation, since the core body 44 with a highstiffness is embedded in the swell portion 42 d, the upper side part ofthe hollow portion 43 located in the upper position remains uncollapsedto thereby elastically deform the rubber portion on a side of the upperside part of the hollow portion 43 with comparative ease.

Therefore, even if the rubber block portion 42 b and the rubber wallportion 42 c both compressed in the vehicle body longitudinal directionare in a state with difficulty in elastic deformation, the upper sidepart of the hollow portion 43 remaining uncollapsed expands or shrinksto enable the core body 44 to revolve (a link action) around an axis inthe vehicle body traverse direction as a link and to thereby enable therear side stopper rubber 42 in the entirety to shear-deform in thevertical direction with comparative ease, therefore, enabling verticalvibrations between the mount body potion 30 and the stopper metal member40 to be sufficiently absorbed.

Note that in a state where the rear side stopper rubber 42 receives nopushing force in the vehicle body longitudinal direction as describedabove, the core body 44 can revolve around an axis in the vehicle bodytraverse direction with ease by expansion and shrinkage of the hollowportion 43 with ease: for example, by an angle of about 1 degree or morerelative to the casing body 31 a. In the construction described above,the core body 44 is embedded in the rubber swell portion 42 d, while,without limiting to this, a construction may be adopted in which part ofthe core body 44 is embedded in the swell portion 42 d and the otherpart thereof is embedded in the body of the rubber wall portion 42 c.

—Action and Effect—

With the construction adopted, according to the vibration isolatingproof device (the engine side mount 3) related to the embodiment 1, forexample, when an automobile is at rest and the engine 1 is in an idlingstate, idling vibrations of low frequencies caused by a change in torqueor the like are absorbed by the rubber elastomer 33 of the mount body 30to thereby suppress transmission of the vibrations to the vehicle body.In this situation, for example, since, in the engine side mount 3, thestopper rubbers 41 and 42 or the like of the mount body 30 are spacedapart from the stopper metal member 40, no idling vibration istransmitted to the vehicle body therethrough.

On the other hand, when a large driving reaction force (torque) such as,for example, that in rapid acceleration of an automobile, the powerplant P tends to sway as a whole like a pendulum with the oscillationsupport axis L thereabove as a center forward or rearward while rollingalmost around the roll axis R as shown as a model with a open arrow markin FIG. 2. On this occasion, a displacement in revolution around theroll axis R is not only restricted by the independent torque rod 8 inthe lower end portion of the power plant P, but also suppressed by theoscillation limiting mechanisms in the left and right mounts 3 and 5,thereby suppressing oscillation of the power plant P effectively.

In this situation, for example, in the oscillation limiting mechanism 4in the engine side mount 3, since the rear side stopper rubber 42 isplaced in a state of being brought into contact with the stopper metalmember 40 to receive a compressive force in the vehicle bodylongitudinal direction, there arises a risk that vibrations in verticaldirection of the power plant P is transmitted to the vehicle bodythrough the rear side stopper rubber 42, while the rear side stopperrubber 42, as described above, can be shear-deformed in the verticaldirection with comparative ease even by receiving a compressive force inthe vehicle body longitudinal direction since the stepped hollow portion43 and the core body 44 in the rear side rubber stopper 42 cooperatewith each other and cause a link action.

With such workings in effect, a rise in dynamic spring constant in thevertical direction of the mount 3 as a whole is quite smaller even ifthe stopper works and transmission of the vibrations in the verticaldirection to the vehicle body is effectively suppressed even ifvibrations in the vertical direction of the power plant P increase byrapid acceleration of the engine; therefore causing a surrounding soundin the vehicle compartment due to acceleration to be suppressed so asnot to become especially intense.

FIGS. 7A and 7B show results of investigation on a change in springcharacteristic of a vibration proof mount before and after action of thestopper in company with acceleration and deceleration of an automobileas described above, wherein FIG. 7A is a graph showing a load vs.displacement (bending) curve showing a change in a static springconstant in the vehicle body longitudinal direction and FIG. 7B is agraph showing a change in a dynamic spring constant in the verticaldirection before and after the action of the stopper.

The curve shown with a solid line (I) in FIG. 7A is of a conventionalgeneral stopper made of a solid rubber, wherein it is understood that aninclination of the curve is mild and a spring is soft till the stopperacts at a low acceleration, while an inclination of the curve risessteeply when the stopper acts (a point S1 in the figure) and a stiffnessof a compressed rubber increases drastically. Since a static springconstant automatically increases in the vertical direction when a staticspring constant increase in the vehicle body longitudinal direction asdescribed above, a dynamic spring constant in the vertical directionrapidly increases as shown with a solid line (I) in FIG. 7B to greatlydegrade an absorption performance of vibrations in the verticaldirection in a state where a set load corresponding to a predeterminedacceleration state of an automobile acts as shown with an alternate longand short dash line in FIG. 7A, (shown with a dotted line is the dynamicspring constant in the vertical direction without a load acting in thevehicle body longitudinal direction).

A curve shown with a broken line (II) in FIG. 7A is of a case where ahollow portion is provided in a stopper rubber as is disclosed in eachof conventional examples (Patent literatures 5 and 6) to thereby reducea stiffness partly, wherein since a rise in a spring constant in thevehicle body longitudinal direction at an initial stage of action of thestopper (S2) is mild as compared with that of the solid rubber (I), aninclination of a curve is comparatively mild even when the set load actsand a softer spring characteristic is achieved as compared with that ofa solid rubber. In this case as well, however, a dynamic spring constantin the vertical direction increases as shown with the broken line (II)in FIG. 7B corresponding to a rise in a spring constant in the vehiclebody longitudinal direction of the stopper rubber; therefore,degradation in absorption performance for vibrations in the verticaldirection cannot be avoided.

In contrast to this, since in a case of the stopper rubber 42 in theembodiment 1, the core body 44 performs a link action as described aboveto thereby enable a rise in dynamic spring constant in the verticaldirection to be sufficiently suppressed while receiving and absorbing aforce in the vehicle body longitudinal direction with certainty in asimilar way to that of a torque rod, it is understood that a low dynamicspring constant in the vertical direction can be achieved that is closeto that when no set load acts in the vehicle body longitudinal directionas shown with an alternate long and short dash line (III) in FIG. 7Beven in a state where the set load acts in the vehicle body longitudinaldirection acts. Note that an alternate long and two short dashes line(IV) in FIG. 7B shows a dynamic spring constant in the verticaldirection in the embodiments 2 and 3 described later.

Therefore, with the oscillation limiting mechanism 4 in the vibrationisolating proof device 3 related to the embodiment 1, a function similarto that of a torque rod can be obtained by a link action of the corebody 44 embedded in the stopper rubber 42 while cost up is prevented ina simple structure similar to that of a conventional general stoppermechanism, whereby absorption performance for vibrations in the verticaldirections by the mount 3 can be maintained while oscillation of thepower plant P is effectively restricted even if the power plant Poscillates; thereby enabling increase in surrounding sound inacceleration to be prevented.

In this embodiment, not only is the stopper metal member 40 in the shapeof an inverted U letter provided so as to cross over the mount bodyportion 30 of the vibration proof mount 3, but the stopper rubbers 41,42 and 45 in the vehicle body longitudinal and vertical directions arealso integrally with the casing 31 of the mount body portion 30 in asingle piece, and thereby as well reduction in cost can be realized.

—Example Modification—

In the embodiment 1 described above, a shape of the core body 44 of therear side stopper rubber 42 is unnecessary to be in the shape of arectangular plate and may be, for example as shown in FIG. 8, in thesectional shape where the core body 44 protrudes forward almost in themiddle thereof in the vehicle body traverse direction as viewed fromabove. With such a shape adopted, the swell portion 42 d swelling inwardin the hollow portion 43 also protrudes forward in the middle thereof inthe vehicle body traverse direction to thereby reduce a contact area ofthe swell portion 42 d with the rubber block portion 42 b located beforethe swell portion 42 d in a state where the rear rubber stopper 42 ispushed in the vehicle body longitudinal direction; therefore causing thecore body 44 to move with more of ease.

In the rear side stopper rubber 42, the hollow portion 43 is formed soas to pass therethrough vertically and the swell portion 42 d isprovided in the lower side thereof, while without limiting to this, theswell portion 42 d can also be provided in the upper side of the hollowportion 43.

In the rear side stopper rubber 42, the core body 44 is embedded in therubber wall portion 42 c, while it can also be embedded in the rubberblock portion 42 b, with which construction the core body 44 revolvesmainly relative to the stopper metal member 40.

In the rear side stopper rubber 42 of the embodiment 1, the core body 44performs a link action in cooperation with the hollow portion 43, towhich a construction is not necessary limited. That is, in a case wherea length A of the core body 44 embedded in the stopper rubber 42 in thevehicle body longitudinal direction, as shown as a model in FIG. 9, islonger than a length B in the vertical direction (A≧B), the core body 44revolves around an axis in the vehicle body traverse direction withcomparative ease even if the core body 44 receives a compressive forcein the vehicle body longitudinal direction; therefore, enabling anaction and effect similar to those in the embodiment 1 to be acquired.

Embodiment 2

FIGS. 10 to 13 show an engine side mount 3 in the embodiment 2 of theinvention of the present application. In the embodiment 2, as clear fromthe figures, no hollow portion 43 is provided in the rear side stopperrubber 42 of the oscillation limiting mechanism 4 and instead, astructure of the rubber portion in which the core portion is embedded iscontrived so as to cause the core body 44 to perform a link action. Notethat since a construction of the mount 3 in the embodiment 2 is the sameas in the embodiment 1 except for details a structure of the rear sidestopper rubber 42, the same marks are attached to the same constituentsand descriptions thereof are omitted in the following passages of thespecification.

Then, description will be detailed of a structure of the rear sidestopper rubber 42 with reference to FIGS. 13A and 13B. The rubberportion of the rear side stopper rubber 42 is, as shown with a sectionin FIG. 13A, constructed from a connecting rubber portion 42 b (aconnecting portion) formed so as to connect the core body 44 in theshape of a rectangular plate to the casing body 31 a and a protrudedrubber portion 42 c (a protruded end portion) formed so as to protrudetoward the rear side of the vehicle body from the rear side of the corebody 44 and has the shape of a inverted L letter as a whole.

The connecting rubber portion 42 b is formed as far as a length of abouttwo-thirds of the core body 44 downward from the top end portion thereofand the upper side portion thereof in a relative sense including thecentral part of the core body 44 is connected to the casing body 31 a.In other words, the core body 44 is separated from the casing body 31 ain a portion in the side thereof lower than the connecting rubberportion 42 b; thereby enabling the core body 44 to revolve (a linkaction) around an axis in the vehicle body traverse direction withcomparative ease (for example, the core body 44 can revolve relative tothe casing body 31 a by an angle of about 1 degree or more in a statewhere no compressive force acts).

On the other hand, the protruded rubber portion 42 c on the other sidefrom the connecting rubber portion 42 b is formed as far as a length ofabout two-thirds of the length of the core body 44 upward from the lowerend portion thereof, that is in a portion in the lower side of the corebody 44 in a relative sense including the central part thereof. That is,the protruded portion 42 c and the connecting rubber portion 42 b notonly sandwich the core body 44 from the front and rear sides, andoverlap one on the other in the vicinity of the central part of the corebody 44 in the vertical direction, but are also shifted with respect tocentral position in the vertical direction to assume an offsetarrangement.

With such a construction, in a case where the mount body portion 30 isdisplaced rearward as shown in FIG. 13B, and the rear end surface of theprotruded rubber portion 42 c, that is the rear end portion of the rearside stopper rubber 42, is brought into contact with the rear side legportion 40 c of the stopper metal member 40, whereby a pushing force inthe vehicle body longitudinal direction is received, the pushing forcein the vehicle body longitudinal direction can be received withcertainty since the connecting rubber portion 42 b and the protrudedrubber portion 42 c are overlapped one on the other in the vicinity ofthe central part of the rear side stopper rubber 42 in the verticaldirection.

Since the connecting rubber portion 42 b and the protruded rubberportion 42 c sandwiches the core body 44 and are shifted in an offsetarrangement in the vertical direction, an axial line of a pushing forcef1 acting on the rear side stopper rubber 42 from the leg portion 40 cof the stopper metal member 40 in the vehicle body longitudinaldirection and an axial line of a reaction force f2 from the casing body31 a, as shown in the figure, does not coincide with each other,revolution of the core body 44, that is a link action of the core body44, is urged by the couple of forces f1 and f2.

Therefore, in the embodiment 2 as well, when the rear side stopperrubber 42 receives a pushing force in the vehicle body longitudinaldirection as described above, the stopper rubber 42 as a wholeshear-deformed in the vertical direction by the link action of the corebody 44 with comparative ease in a similar way to that in the embodiment1 even in a state where the rubber portions 42 b and 42 c are compressedto be thereby hard in elastic deformation; thereby enabling displacementof the mount body portion 30 relative to the stopper metal member 40 inthe vertical direction to be sufficiently allowed and further vibrationsin the vertical direction to be effectively absorbed.

In the embodiment 2, besides, since a link action of the core body 44 isprompted by the pushing forces f1 and f2 in the vehicle bodylongitudinal direction, a rise in dynamic spring constant in thevertical direction can be more suppressed even as compared with that inthe embodiment 1, and as shown with an alternate long and two shortdashes line (IV) in FIG. 7B, a low dynamic spring characteristic in thevertical direction is not so much different from that when no load actsin the vehicle body longitudinal direction can be achieved even in acase where a predetermined pushing force (a set load) acts in thevehicle body longitudinal direction.

Note that in the rear side stopper rubber 42, various parameters such asa ratio of the connecting rubber portion 42 b to the core body 44 inlength in the vertical direction, a level of offset between theconnecting rubber portion 42 b and the protruded rubber portion 42 c, adimension ratio between a length and width of the core body 44 or thelike can be altered, thereby enabling a balance between a supportstiffness in the vehicle body longitudinal direction and an easiness inshear deformation in the vertical direction to be altered.

—Example Modification—

In the embodiment 2 as well, a shape of the core body 44 in the rearside stopper rubber 42 may not be in the shape of a rectangular plateand for example, may be in the shape of a crank in section as shown inFIG. 14A. A hollow portion 42 d is formed in the interior of the rubberas shown in, for example, FIG. 14B instead of forming the rubberportions (the connecting rubber portion and the protruded portion) 42 band 42 c before and after the core body 44 as shown in the FIGS. 14A and13A shifted from each other in the vertical direction, and the centersof gravity of the rubber portions before and after the core body 44 orapplication points of forces in the rubber portions may be shifted fromeach other in the vertical direction.

As shown in FIGS. 14C and 14D, the core body 44 in the rear stopperrubber 42 is formed in the shape of a crank in section as viewed in thevehicle body traverse direction and the front end portion and rear endportion may be shifted in an offset arrangement vertically oralternatively, the core body 44 may also be inclined so as to shift thefront end side and rear end side thereof in position in the verticaldirection.

Embodiment 3

FIGS. 15 to 17 show the embodiment 3 of the invention of the presentapplication and, as shown in FIG. 16, especially in an engine side mount3′ of the embodiment 3, a mount body portion receiving a static load ofthe power plant P is disposed in a construction inverted upside down inthe vertical direction from the constructions in the embodiment 1 and 2,wherein a metal casing 60 is connected to the vehicle body, while on theother hand, a connecting metal member 64 is connected to the power plantside. Note that an overall construction of the engine mount system ofthe embodiment 3 is the same as in the embodiments 1 and 2 except for astructure of the engine side mount 3′; therefore, the same marks areattached to the same constituents and descriptions of thereof areomitted.

—Structure of Engine Side Mount—

Then, detailed description will be given of the structure of the engineside mount 3′ with reference to FIGS. 16 and 17 and in addition, FIGS.18 and 19. The casing 60 is, as shown in FIG. 16, constructed from: asupport cylinder 61 in the shape of a cylinder supporting the connectingmetal member 64 from below with a rubber elastomer 63 interposedtherebetween; and a stopper metal member 62 having the shape of acylinder slightly smaller in diameter than the support cylinder 61, aflange 62 a formed in the lower end potion of which is fixed to the topend portion of the support cylinder 61, wherein the support cylinder 61is fixed on a side frame 6 with three brackets 67, 67 and 67 fixedlyattached to the outer circumference in the lower side of the casing 60in a single piece.

The support cylinder 61 has a double structure constructed from an innercylindrical member 65 in the inner side and an outer cylindrical member66 in the outer side and plural (eight mails in the figure) nailportions 60 a, 60 a, . . . protruding upward from the top end edge ofthe outer cylindrical member 66 in the top end portion thereof areprovided at a predetermined spacing in the peripheral direction and thenail portions 60 a are bent toward the inner circumference side tothereby caulk the lower portion flange 62 a on the top end edge of theinner cylindrical member 65. On the other hand, annular inner peripheralflanges 65 a and 66 b extending toward the inner circumference side areformed at the lower end edge portions of the inner cylindrical member 65and the outer cylindrical member 66, and the inner peripheral flange 65a of the inner cylindrical member 65 is caulked on the inner peripheralflange 66 b of the outer cylindrical member 66 from below.

The connecting metal member 64 is not only formed in the shape ofinversion of a frustum of circular cone which is gradually tapereddownward in the lower side portion, but also housed in the casing 60 andadhered to the upper portion of a rubber elastomer 63, while on theother hand, a portion in the upper side extends upward from the topsurface of the casing 60 to serve as a connection shaft portion 64 a inwhich a bolt hole 64 b is formed in the shaft portion 64 a so as todirect downward along the axial line Z from almost the central part ofthe top end surface thereof. Though not shown, an engine mountingbracket 29 (screwed on the top end portion of the mount bracket 15 whichis shown only in FIG. 15) is fastened on the top end of the connectingmetal member 64 with a mounting bolt screwed in the bolt hole 64 b.

On the other hand, the inner circumference of the top portion of therubber elastomer 63 is cure-adhered to the lower portion of theinversion of a frustum of circular cone of the connecting metal member64 across the entire circumferential surface of the frustum of acircular cone. The outer circumference of the top portion of the rubberelastomer 63 is formed in the shape of a frustum of a circular conetapered upward and an annular stopper portion 80 (described later)swelling outward is integrally provided at the top end thereof in asingle piece. A rubber thin layer portion 63 a is formed so as to extenddownward from the lower end of the rubber elastomer 63 and the thinlayer portion 63 a is cure-adhered on the inner circumference of thelower end portion of the inner cylindrical member 65. Therefore, theconnecting metal member 64 is supported from below by the casing 60 withthe rubber elastomer 63 interposed therebetween.

An orifice plate 68 in the shape of a near disk with a large thicknessis press-inserted from below on the inner circumferential surface of thethin layer portion 63 a and a diaphragm 69 in the shape of a hat isdisposed on the lower side of the orifice plate 68 so as to cover all ofthe lower side of the orifice plate 68 from below, whereby a lower endopening of the rubber elastomer 63 is liquid-tightly closed to form acavity portion therein. That is, the diaphragm 69 is a filmy member madeof rubber, a reinforcing plate 70 in the shape of an annular plate isembedded in an outer peripheral portion 69 a with a relatively largerthickness, the outer peripheral portion 69 a is superimposed on theupper surface of the inner peripheral flange 65 a formed at the lowerend of the inner cylindrical member 65, and the inner peripheral flange65 a are caulked on the inner peripheral flange 66 b of the outercylindrical member 66.

A shock-absorbing liquid is sealed in the cavity portion of the rubberelastomer closed by the diaphragm 69 and the cavity portion serves as aliquid chamber F for absorbing and alleviating vibrations. The internalspace of the liquid chamber F is partitioned by the orifice plate 68into two smaller spaces one on the other and the upper side space worksas a pressure receiving chamber, while the lower side space works as anequilibrium chamber. An orifice passage 71 in a structure of a doublehelix is formed in the outer peripheral portion of the orifice plate 68closed with the thin layer portion 63 a of the rubber elastomer 63adhered to the inner circumferential surface of the inner cylindricalmember 65 of the casing 60, and the upper end of the orifice passage 71faces and is open in the pressure receiving chamber, while on the otherhand, the lower end of the orifice passage 71 faces ad is open in theequilibrium chamber.

—Oscillation Limiting Mechanism—

As shown in FIGS. 16 and 17, an oscillation limiting mechanism 4′ isintegrally provided in the engine side mount 3′ in a single piece. Thatis, a stopper portion 80 (a vehicle body longitudinal force receivingmember) constructed from a rubber member and others, as described above,is formed on the outer circumferential side of the connecting shaftportion 64 a of the connecting metal member 64 surrounded with thestopper metal member 62 of the casing 60, and, when the power plant Poscillates in the vehicle body longitudinal direction, is brought intocontact with the stopper metal member 62 and receives a force in thevehicle body longitudinal direction.

Detailed description will be given of a structure of the stopper portion80 with reference to FIGS. 16 to 19, wherein the rear side of thestopper portion 80 is different from the front side thereof only inposition in height of the core body 81 and has the same function of thecore body 81 revolving like a link as the front side thereof; thereforein FIG. 19, there is shown a section of only the front side of thestopper portion 80 and description is given of only the front side.

The stopper portion 80, as shown in FIGS. 16 and 19A, is constructedsuch that a metal core body 81 (see FIG. 18A) in the shape of a nearrectangle in section and a near U letter as viewed from above isembedded in the interior of an annular rubber layer formed on the outercircumferential surface of the connecting metal member 64 integrallywith the rubber elastomer 63 in a single piece, and disposed so as tosurround the connecting shaft portion 64 a across more than a half ofthe circumference from the right side wherein the front portion 81 a andthe rear portion 81 b of the core body 81 are located at positions atthe front side and rear side of the connecting shaft portion 64 a.

Note that in the sectional view, as shown FIGS. 16 and 19A, a rubberportion 82 a on the inner circumferential side of the core body 81 isthicker than a rubber portion 82 b on the outer circumferential sidethereof. An upward swell portion 80 a raised upward is provided to thestopper portion 80 and by bringing the upward swell portion 80 a intocontact with the upper flange portion 62 b of the stopper metal member62 from below, upward movement of the connecting metal member 64 islimited there.

The core body 81 is obliquely inclined at a predetermined angle δrelative to a horizontal plane in the vehicle body longitudinaldirection (in this embodiment, a plane X intersecting with the axialline Z of the mount 3 at a right angle) so that the front portion 81 ais located lower than the rear portion 81 b. This is because even in acase where a force in the vehicle body longitudinal direction acts tobring the stopper portion 80 into contact with the inner circumferentialsurface of the stopper metal member 62, the core body 81 is caused toperform a link action as described below while receiving a force in thevehicle body longitudinal direction, and for the link action of the corebody 81, the core body 81 is preferably set so as to be inclined at anangle δ in the range of, for example, from about 3 to about 5 degrees.

In order to dispose the core body 81 is in an inclined state, thestopper portion 80 is formed in a way that the mount 3 is invertedupside down so that the connecting shaft portion 64 a of the connectingmetal member 64 assume a lower position and in this state, the rubberportion 82 and the rubber elastomer 63 are cure-molded while the corebody 81 is supported by plural pin members (not shown) from below.Therefore, plural holes 82 c being open upward are formed at sitescorresponding to the pin members on the rubber portion 82. In order thatthe core body 81 is inclined (the front portion 81 a is lower than therear portion 81 b), supporting heights of the plural pin members are setdifferently between the front side and rear side of the core body 81.Hence, in a case where the outer form of the rubber portion 82 of thestopper portion 80 is symmetrical in the vehicle body longitudinaldirection, the depth of a hole 82 c formed in the front side of the corebody 81 is deeper than a hole 82 c formed in the rear side thereof.

Note that a molding method for the stopper portion 80, without beinglimited to the above method, may also be performed in a state where theconnecting metal member 64 takes a position of FIG. 16 (the connectingshaft portion 64 a is positioned at an upper position). In this case,since the core body 81 is supported by the pin members from below, theholes 82 c are formed so as to be open at the lower surface of therubber portion 82.

With such an inclination of the core body 81 in the vehicle bodylongitudinal direction, in a case where, for example, in rapidacceleration or rapid deceleration of an automobile, the connectingmetal member 64 is displaced forward as shown in FIG. 19B in companywith oscillation of the power plant P and the outer circumferentialportion of the stopper 80 is brought into contact with the innercircumferential surface of the stopper metal member 62 to receive apushing force in the vehicle body longitudinal direction, the pushingforce f1 from the stopper metal member 62 acts to the core body 81obliquely relative thereto to thereby urge the core body 81 to performrevolution (a link action).

That is, even in a case where a pushing force in the vehicle bodylongitudinal direction acts on the stopper portion 80 to therebycompress the rubber portions 82 a and 82 b on the outer and innercircumferential sides of the core body 81 in the vehicle bodylongitudinal direction so as to be difficult in elastic deformation, thecore body 81 in the inclined state revolves around an axis in thevehicle body traverse direction to thereby shear-deform the stopperportion 80 as a whole in the vertical direction with comparative ease.With such a construction, even when the stopper portion 80 receives apushing force in the vehicle body longitudinal direction, the connectingmetal member 64 on the power plant P side and the stopper metal member62 on the vehicle body side are displaced relatively to each other withcomparative ease, thereby enabling vibrations in the vertical directionto be absorbed effectively.

In the stopper portion 80, the outer circumferential surface 81 c of thecore body 81 (including the front and rear end surfaces of the core body81) is almost parallel to the inner circumferential surface of thestopper metal member 62 and since when the outer circumferential surfaceof the stopper 80 is brought into contact with the inner circumferentialsurface of the stopper metal member 62, the outer circumferentialsurface 81 c of the core body 81 pushes the rubber portion 82 b in theouter circumferential side with a uniform force; therefore, enablingdamage on the rubber portion 82 b to be prevented.

Note that, as shown in FIG. 18B, the outer circumferential surface 81 cof the core body 81 may assume a surface with a circular arc in sectionswelled in the middle of the vertical width. In this case, not only candamage on the protruded rubber portion 82 b be effectively prevented,but a link action of the core body 81 as described above is also occurswith extreme ease, thereby enabling vibrations in the vertical directionto be absorbed effectively. Herein, the outer circumferential surface 81c of the core body 81 almost in parallel to the inner circumferentialsurface of the stopper meal member 62 is a planar portion, while in acase where the outer circumferential surface 81 c is in the shape of acircular arc in section swelled in the middle of the vertical width, theouter circumferential surface 81 c is a curved surface portion having asection of a circular arc.

Therefore, even in a case where in the engine side mount 3′ of theembodiment 3, the stopper portion 80, as described above, receives apushing force in the vehicle body longitudinal direction and the rubberportions 82 a and 82 b assumes a state of being difficult in elasticdeformation under an influence of a compressive force, the core body 81performs a link action in a similar way to that in the first orembodiment 2 to thereby cause the stopper portion 80 as a whole toelastically deform in the vertical direction with comparative ease tothereby reduce a rise in dynamic spring constant in the verticaldirection to a very small value; therefore, enabling transmission ofvibrations in the vertical direction from the power plant P to thevehicle compartment to be suppressed and further increase in asurrounding sound in acceleration to be suppressed.

Since a link action of the core body 81 in the engine side mount 3′ inthe embodiment 3 is urged by a pushing force f1 in the vehicle bodylongitudinal direction in a similar manner to that in the engine sidemount 3 of the embodiment 2, a rise in dynamic spring constant in thevertical direction can be reduced to the lowest value even in a statewhere a predetermined pushing force (a set load) acts in the vehiclebody longitudinal direction as shown with an alternate long and twoshort dashes line (IV) in FIG. 7B.

In the embodiment 3, the stopper portion 80 constructed from the corebody 81 formed in the shape of a near U letter as viewed from above andthe rubber stopper 82 is provided so as to surround the connecting metalmember 64 from the side all therearound to thereby exert a similarfunction to that of a torque for inclination in any sense in the vehiclelongitudinal direction and to therefore, facilitate fabrication ascompared with a case where separate members are provided at the frontand rear side; thereby enabling a cost to be reduced.

Other Embodiments

A construction of the present invention is not limited to theembodiments described above, but includes various kinds of otherembodiments. Therefore, while in any of the embodiments 1 to 3, the corebody 44 or 81 is made of a metal, to which no specific limitation isapplied, and may be made of any material, for example a resin, since amaterial of the core body 44 or 81 has only to be higher in stiffnessthan rubber.

In the embodiments 1 and 2, a hollow portion 43 is provided only in therear side stopper rubber 42 of the stopper rubbers 41 and 42 in thefront and rear sides and the core body 44 is embedded to therebyconstruct the oscillation limiting mechanism 4, to which no specificlimitation is applied, while a construction can be adopted in which thefront side stopper rubber 41 can be constructed in a similar way to thatin the rear side.

In addition, while in each of the embodiments, the engine side mount 3or 3′ is of a liquid sealed type, to which no specific limitation isapplied and needles to say that a construction may be adopted in whichfor example, the partition plate 36, the orifice plate 68, thediaphragms 37 and 69 and others are removed from the casings 30 and 60of the mount body to thereby support a static load of the power plant Ponly by the rubber elastomers 33 and 63.

According to a vibration isolating proof device related to the presentinvention, as described above, oscillation of the power plant P in rapidacceleration or the like is restricted by the oscillation limitingmechanism 4 or 4′ integrally provided to the mount 3 supporting thepower plant P in a single piece and even in such a state, vibrations inthe vertical direction can be effectively absorbed and increase insurrounding sound in acceleration and the like in the vehiclecompartment can be suppressed; therefore, the vibration isolating proofdevice can be employed as a mount system for a FF automobile and isextremely useful especially in a pendulum mount.

1. A vibration isolating proof device for elastically supporting a powerplant mounted on a vehicle with a length direction of the power plantaligned in a traverse direction of a body of the vehicle, the vibrationisolating proof device having an oscillation limiting mechanism forlimiting oscillation of the power plant in a roll direction thereof;wherein the oscillation limiting mechanism has a receiving member for aforce in a vehicle body longitudinal direction receiving a compressiveforce in the vehicle body longitudinal direction between a member of thevehicle body and a member of the power plant facing each other in thevehicle body longitudinal direction in company with rolling of the powerplant, the receiving member is constructed of: a rubber portion and acore body made of a material higher in stiffness than the rubber portionand provided integrally with the rubber portion in a single piece atleast so as to be revolvable around an axis in the vehicle body traversedirection by a predetermined angle or more and configured such that anapplication point of a force from the front side of the vehicle body tothe core body in the rubber portion is shifted from an application pointof a force from the back side of the vehicle body to the core body whenthe receiving member receives the compressive force in the vehicle bodylongitudinal direction, and the receiving member becomes shear-deformedin a vertical direction with the core body revolved around the axis byreceiving the compressive forces from the front and rear sides of thevehicle body even when the receiving member is compressed in the vehiclebody longitudinal direction because of rolling of the power plant. 2.The vibration isolating proof device of claim 1, wherein a hollowportion is formed in the rubber portion of the receiving member at leastso that the core body can be revolved around an axis in the vehicletransverse direction.
 3. The vibration isolating proof device of claim1, wherein the rubber portion in the receiving member includes: aconnecting portion connecting the core body to one of the member of thevehicle body and the member of the power plant; and a protruded endportion directed to the other member thereof from the core body, whereinthe connecting portion and protruded end portion are vertically shiftedin an offset arrangement.
 4. The vibration isolating proof device ofclaim 1, wherein the core body in the receiving member is inclined sothat the front end portion and rear end portion are vertically offset inposition.
 5. The vibration isolating proof device of claim 1, whereinthe vibration isolating proof device is arranged at an end portion ofthe length direction of the power plant so as to be spaced upward from aroll axis of the power plant.
 6. A vibration isolating proof device forelastically supporting one of left and right end portions of a powerplant mounted on a vehicle with a length direction of the power plantaligned in a traverse direction of a body of the vehicle, the vibrationisolating proof device having an oscillation limiting mechanism forlimiting oscillation of the power plant in a roll direction thereof,wherein the oscillation limiting mechanism has a receiving member for aforce in a vehicle body longitudinal direction receiving at least acompressive force in the vehicle body longitudinal direction between amember of the vehicle body and a member of the power plant facing eachother in the vehicle body longitudinal direction, the receiving memberis constructed of: a rubber portion and a core body made of a materialhigher in stiffness than the rubber portion and provided integrally withthe rubber portion is a single piece at least so as to be revolvablearound an axis in the vehicle body traverse direction by a predeterminedangle or more, wherein the core body in the receiving member is acrank-like shape as viewed in the vehicle body traverse direction andthe front end portion and the rear end portion are vertically shifted inan offset arrangement, such that the core body is provided to berevolved around an axis in the vehicle body traverse direction whenreceiving the compressive force acting between a member of the vehiclebody and a member of the power plant, and the receiving member easilybecomes shear-deformed in a vertical direction owing to revolving of thecore body even when the receiving member is compressed in the vehiclebody longitudinal direction because of rolling of the power plant.